Why am I getting error in event function for impulsive differential equations?

Question

Rakesh 2022-6-13

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1739690-why-am-i-getting-error-in-event-function-for-impulsive-differential-equations

编辑： Torsten 2022-6-14

function  sol = paper_impulse
t0 = 0; t1 = 5; 
impcount = 0; te=1; k=1; No = 1; ep=0.01; vec = []; x = []; i=0; impulse_strength = 1.2;
v=zeros(201);
while(i<5)
    i = i+0.01;
    x = [x, i];
end
disp(x)
x= round(x*100)/100;
while true
         if (impcount ==0)
            options = odeset('Events',@events,'AbsTol',1e-5,'RelTol',1e-5);
            
            sol = ode45(@neural_network, [t0, t1], [3 5], options);
            
          else
            % Specify the new solution at impulse times...
            
            options = odeset(options,'InitialY',[impulse_strength*sol.y(1,end) impulse_strength*sol.y(2,end)]);
            sol = ode45(@neural_network, [t0, t1], sol, options);              
         end
         t0 = sol.x(end);
         fprintf('Restart at %5.2f.\n',t0);
         vec = [vec,te];
         ind = find(abs(x-te)<0.001);
         v(ind) = v(ind) + impulse_strength;
         fprintf('Restart at %5.2f.\n',ind);
         k=k+1;
         if(mod(k,No) == 0)
             te = te+ No*(0.02-ep)+ep;
         else
             te = te+ ep;
         end 
         
         impcount = impcount + 1;
        
         if (t0 >= t1)
            
            break;
         end
         
end
plot(sol.x, sol.y(1,:));
hold on
plot(sol.x, sol.y(2,:));
%disp(size(vec));
%stem(vec, v);
%axis([1 5 0 impulse_strength*2]);
%xlabel('time');
%ylabel('impulse strength');
function dy = neural_network(t,y)
  dy = zeros(2,1);
  
  dy(1) = -1/2*y(1)-y(1).^3+y(1).*y(2).^2-((y(1).^2+y(2).^2).^1/4).*sign(y(1));
  dy(2) = -1/2*y(2)-y(2).^3-y(2).*y(1).^2-((y(1).^2+y(2).^2).^1/4).*sign(y(2));
end
function [value,isterminal,direction] = events(t,y)
         value = t-te;
         isterminal = 1;
         direction  = 0;
end
 end
    

The above code is for impulsive differential equation. I have used the event function to locate the moments at which the solution has jump kind of discontinuites. But code is compiling with errors. Please help to short out this problem.